Tin-Based composite Materials Fabricated by Anodic Oxidation for the Negative Electrode of Li-Ion Batteries

We report an easy, inexpensive and environmentally clean route for fabricating tin-based composite materials with complex texture using anodic oxidation of bulk tin foils in an electrolyte bath based on polyethylenglycol and oxalic acid in the trans-passive region. Electron microscopy data reveal micrometric particles with a complex texture at the nano scale, which is preserved after annealing at 350°C. The characterization by X-ray diffraction and 119 Sn Mössbauer spectroscopy showed that the materials consisted of mixtures of tin and tin oxides with amorphous and crystalline structures. Their potential application as negative electrodes for Li-battery in terms of capacity and cycle life is evaluated in lithium test cells. The capacity fade due to volume changes during Li alloying and de-alloying can be averted for these Sn-based composite nanostructures. The materials containing a mixture of Sn IV and Sn 0 are particularly attractive for batteries demanding low capacity fading.